1. Field of the Invention
This invention relates to a snow making system (i.e. method and apparatus) capable of producing high quality snow efficiently and in large quantities.
This system can be used in both above- and below-freezing environments (i.e. above- or below 0° C.) to produce man-made snow.
The term “snow” shall be used to include “artificial snow” or “man-made snow”.
2. Prior Art
There has been a long-standing requirement for the economic production of snow at snow fields or ski-resorts where only limited or insufficient natural snow is available e.g. due to lack of moisture in the air, high ambient air temperatures, high ground temperatures, heavy skiing usage or the like.
As natural snow is seasonal, and sufficient natural snow falls cannot be guaranteed (e.g. by the opening of the local skiing season), ski resort operators may only have a limited period each year in which they can recoup the capital- and operating costs of their resorts. In addition, potential investors in such resorts may be deterred from investing if they consider the risk of no-snow/insufficient-snow, is too high.
Over the years, many proposals have been put forward for the production of snow in-situ on the snow fields; and examples of earlier proposals by the present inventor (Bucceri) have been disclosed, inter alia, in U.S. Pat. Nos. 4,742,958; 4,973,142; 5,297,731; 6,454,182; 6,938,830; 6,951,308; 7,484,373; and 8,403, 242; together with US Patent Application Publications US 2003/0181248 A1; & US 2005/0035210 A1. These publications reflect over 20 years research & development in the field of producing snow by the present inventor
At temperatures below −5 degrees Celsius (−5° C.), conventional “state-of-the-art” snow making machines, as discussed below, can be operated whereby water particles, ejected out of the water nozzles on the machines, are mixed with a large volume of ambient air and blown into the sky to allow sufficient “hang-time” for the water particles to yield sufficient heat energy to the ambient air to enable the water particles to freeze into ice crystals and snow.
“A modern snow fan usually consists of one or more rings of nozzles which inject water into the fan air stream. A separate nozzle or small group of nozzles is fed with a mix of water and compressed air and produces the nucleation points for the snow crystals. The small droplets of water and the tiny ice crystals are then mixed and propelled out by a powerful fan, after which they further cool through evaporation in the surrounding air as they fall to the ground. The crystals of ice act as seeds to make the water droplets freeze at 0° C. (32° F.). Without these crystals the water would supercool instead of freezing. The ratio of ice to water is typically 12 parts water: 1 part ice seeds produced by an on-board air compressor or an external compressed air source. This method can produce snow when the wet-bulb temperature of the air is as high as −2° C. (28.4° F.). The lower the air temperature is, the more and the better snow a snow cannon can produce. This is one of the main reasons snow cannons are usually operated in the night. The quality of the mixing of the water and air streams and their relative pressures is crucial to the amount of snow made and its quality.” (Reference: http://en.wikipedia.org/wiki/Snowmaking)
International Publication WO 2014/146009 A2 (Dodson) discloses a Nucleator for Generating Ice Crystals for Seeding Water Droplets in Snow-Making Systems”. The nucleator comprises a mixing chamber for compressed air and water, the compressed air and water mixture is fed to a nucleating block which divides and directs the mixture to a plurality of nozzle channels lying in a plane perpendicular to, and separated from, each other by a select number of degrees; and respective nucleator nozzles, each nozzle connected to a respective nozzle channel, and each nozzle initially further pressurizing the mixture along a convergent portion of the nozzle and then depressurizing the mixture in a divergent portion of the nozzle (at the nozzle outlet) so that the mixture exits the nozzle outlet as tiny ice crystals.
While the nucleator can improve the rate of conversion of water droplets to snow crystals, the snow crystals can still only be formed when the ambient temperature is below the freezing point of water.
While the conventional snow making machines can produce snow, the snow is typically of poor quality; and the machines can only operate when the ambient temperature is low enough.